1. Field of the Invention
This invention relates to a connector terminal press-fitting construction.
2. Description of the Related Art
FIG. 3 shows a connector terminal press-fitting construction disclosed in Japanese Utility Model Unexamined Publication No. Hei. 3-32369.
In this figure, a terminal press-fitting hole 2 for fixedly holding a terminal (male terminal) 3 is formed through a wall 1 of a connector housing. The terminal 3 has a press-fitting portion 6 (serving as a fixing portion) of a greater width provided at intermediate opposite ends thereof. The terminal press-fitting hole 2 has a substantially square shape corresponding to a square cross-section of the press-fitting portion 6 of the terminal 3. Holding portions 5 are formed at opposite side portions of opposed surfaces 2a of the square terminal press-fitting hole 2 which are opposed to each other in a direction corresponding to a direction X of the thickness of the terminal 3. The holding portions 5 extend over the entire length of the terminal press-fitting hole 2. The holding portions 5 hold the press-fitting portion 6 of the terminal 3 in the direction X of the thickness thereof. The distance a1 between the opposed surfaces of each holding portion 5 is slightly smaller than the thickness b1 of the press-fitting portion 6 of the terminal 3.
In this construction, when the press-fitting portion 6 of the terminal 3 is press-fitted into the terminal press-fitting hole 2, portions 7 which are to be held (indicated by hatching), provided respectively at opposite side portions of the press-fitting portion 6 of the terminal 3, are held respectively by the holding portions 5, so that the terminal 3 is fixedly secured to the connector housing.
FIG. 4 shows another conventional construction in which the press-fitting portion of the terminal is slightly modified, and accordingly the shape of the terminal press-fitting hole is slightly modified.
A press-fitting portion 6 of a terminal 13 has a front narrower portion 6a and a rear wider portion 6b greater in width than the narrower portion 6a. A terminal press-fitting hole 12 has a rear narrower portion 14a and a front wider portion 14b which correspond respectively to the narrower portion 6a and the wider portion 6b of the terminal 13. Dimensions g and h of the narrower and wider portions 6a and 6b of the terminal 13 and dimensions k and j of the narrower and wider portions 14a and 14b of the terminal press-fitting hole 12 are so determined that the relation, g&lt;k&lt;h&lt;j, is established. Therefore, with this construction, a holding force, acting in the direction of the width, is not obtained upon press-fitting of the terminal.
Holding portions 15 are formed at opposite side portions of opposed surfaces 12a of the square terminal press-fitting hole 12 which are opposed to each other in a direction corresponding to a direction X of the thickness of the terminal 13. The holding portions 15 extend over the entire length of the terminal press-fitting hole 12 including the wider portion 14b and the narrower portion 14a. The holding portions 15 hold the press-fitting portion 6 of the terminal 13 in the direction X of the thickness thereof. As in the above-mentioned construction, the distance a1 between the opposed surfaces of each holding portion 15 is slightly smaller than the thickness b1 of the press-fitting portion 6 of the terminal 13. The width i of those portions (i.e., relief portions for preventing interference) of the opposed surfaces 12a except the holding portions 15 at the opposite side portions thereof, and the distance n between the opposed surfaces 12a are so determined that the relation, i&lt;g, and the relation, b1&lt;n, are established.
In this construction, when the press-fitting portion 6 of the terminal 13 is press-fitted into the terminal press-fitting hole 12, portions 17 which are to be held (indicated by hatching) of the press-fitting portion 6 of the terminal 13 are held respectively by the holding portions 15, so that the terminal 13 is fixedly secured to the connector housing.
In this case, upon reviewing three stages of the press-fitting process shown respectively in FIGS. 5(a), 5(b) and 5(c), holding forces of the holding portions 15 of the terminal press-fitting hole 12 begin to act on the to-be-held portions 17 of the terminal 13 when a front end 18a of the narrower portion 14a of the press-fitting portion 6 of the terminal 13 reaches an inlet of the terminal press-fitting hole 12 (that is, when the front end 18a begins to interfere with the holding portions 15 as shown in FIG. 5(a), and therefore from this stage, the press-fitting force-must be applied against these holding forces, and the press-fitting force must be increased as the insertion of the terminal 13 proceeds.
Then, from the time when the front ends 18a and 18b of the narrower and wider portions 6a and 6b of the press-fitting portion 6 of the terminal 13 reach the narrower and wider portions 14a and 14b of the terminal press-fitting hole 12, respectively (as shown in FIG. 5(b)), to the time when the press-fitting is completed (as shown in FIG. 5(c)), the press-fitting force must be further increased.
Therefore, in the above conventional construction, when the press-fitting of the terminal 13 is started, the large press-fitting force must be applied from the beginning to the end, and therefore the efficiency of the press-fitting operation is poor. This is the same with the conventional construction of FIG. 3.